The neurological mutants of mice provide a powerful technique for dissecting the complexities of the development of the mammalian central nervous system. A series of mutants will be examined: staggerer, lurcher and leaner. First, a quantitative morphological approach will be used to achieve a fresh perspective on the mutants themselves. In the past this technique has led to such unexpected findings as the absence of 75% of the large cortical neurons of the cerebellar cortex of staggerer. The second area of study will be the examination of mutant yields reversively wild-type cimeras. These unusual animals greatly enhance the power of mouse genetics by providing a situation in which genotypically mutant and wild-type cells coexist in a single mouse. This aids tremendously in the separation of genetic and epigenetic phenomena. The final area of study is to examine the lectin binding properties of cerebellar cryostat sections. Previous work has shown that cerebellar granule cells undergo a change in the carbohydrate characteristics of their cell surface during development. The lectin staining will allow histologcal identification of the structures involved and provide further clues to the role of the cell surface during neural development.